This invention relates to a header transport system for use in transporting a crop harvesting header which may be of a type for attachment to a combine harvester or to a self-propelled tractor unit, or the header may simply be attached to a hitch member for towing by a separate tractor unit.
The present assignees MacDon Industries Ltd. have developed a unique header system known as the "Harvest Header" which is designed for attachment either to a swather tractor for use as a swather header or for attachment to a combine harvester for use as a direct cut header for the combine harvester or in some cases for use in a swathing action while attached to the combine harvester.
One embodiment of this machine is shown in U.S. Pat. No. 5,005,343 of the present assignees. This patent shows the main details of the header including a pair of side drapers which transport the cut crop inwardly from the ends of the header toward a central section. At the central section, when the device is for use with a combine harvester, a feed draper section is attached which feeds the transported crop rearwardly into the feeder housing of the combine harvester. The feed draper section can be removed so the header is then available for use as a centre discharge swather. When mounted on the feeder housing of the combine harvester, the mounting allows limited pivotal movement of the header about an axis parallel to the direction of working movement so that one end of the header can be raised relative to the other end in dependance upon the ground level. The header can of course also be raised and lowered by the conventional lifting action provided on the combine harvester generally by raising and lowering the feeder housing.
In the above patent, the header includes gauge wheels mounted adjacent respective ends of the header for engaging the ground to maintain the end of the header at a predetermined height just above the ground. The gauge wheels are shown simply as small diameter castor wheels of a type which generally have a solid tire and a diameter of the order of nine inches.
Since the filing of the application on which the above Patent issued, further developments have been made to the machine and the machine has been sold in significant numbers in Canada and U.S.A. A brochure showing the machine is submitted on the file of the present application. In this machine as sold, the small diameter gauge wheels have been replaced by larger diameter gauge wheels which are mounted on the header frame so as to trail behind the header frame at a position a short distance inward from the ends of the header. The gauge wheels are mounted for spring action so they are spring biased into contact with the ground but can pivot upwardly relative to the header frame thus allowing the header to float.
The present invention relates to a system for transportation of a header which is particularly but not exclusively designed for use with a header of the type as mentioned above.
It will of course be appreciated that an important aspect of any agricultural machine is the ability to transport the machine at a width that will allow it to move through relatively narrow openings and along roads. It is desirable therefore to provide a machine in the working position having a maximum operating width which in many headers can be as much as thirty to forty feet. At the same time it is necessary to reduce the width of the machine for transportation down to approximately ten feet.
The conventional technique for conversion of a combine harvester from a working position to a transport position is to provide a header transport trailer onto which the header is placed by the lifting mechanism of the combine harvester, following which the header is disconnected from the combine harvester allowing the two pieces to be transported separately. The header is thus towed on the trailer longitudinally while the combine simply drives forward with the header removed. This arrangement is used almost exclusively for combine harvesters having a width of cut which is sufficiently large to make this necessary. The trailer is an accepted technique except for a number of drawbacks. One serious drawback is the fact that the trailer is often in the wrong place. Thus the machine enters the field often at one end, carries out the harvesting operation throughout the field and then wants to leave at an opposite end of the field so that the trailer is parked at the entry end of the field and must be retrieved before transport can take place. Secondly, the correct positioning of the header on the trailer requires significant operator skill. Thirdly the trailer is an additional separate unit involving additional cost.
Swathers of the self propelled type use a different system of transportation but again one involving a transport trailer. In this case the conventional system is to drive the front wheels of the swather tractor, carrying the header, onto the trailer and then to pull the trailer longitudinally that is at right angles to the normal direction of the swather tractor. The rear wheels of the swather tractor then turn by castoring action at right angles to the normal direction to follow the trailer. In this way the swather tractor is towed at right angles to its normal direction.
Pull type swathers include a main frame at one end of which is attached a hitch or coupling to a towing vehicle. The main frame is supported by ground wheels generally positioned at the rear of the main frame at positions spaced apart across the width of working direction. As the ground wheels are designed to support the header frame, it is accepted practice that the ground wheels will also support the same header frame during the transport position. The conversion from working position to transport position is therefore carried out in many designs simply by pivoting the hitch to a transport position about a vertical axis at the rear end of the hitch and at the same time hydraulically pivoting the wheels about respective vertical axes adjacent the rear of the header frame so that the wheels turn from the working direction to a direction substantially at right angles to the working direction for transport.
Canadian Pat. No. 1,226,739 (corresponding to U.S. Pat. No. 4,573,309) assigned to the present assignees shows an arrangement in which the outside wheel is mounted on a crank so that as it is pivoted it also moves forwardly to a position underlying the draper section of the header. The swather therefore becomes a two wheel trailer to be towed longitudinally of the header with the wheel closer to the hitch remaining on the rear side of the centre of gravity and the outside wheel twisted around to the front side of the centre of gravity.
Other examples of conversion systems for transportation of pull type swathers are shown in U.S. Pat. Nos. 3,279,158 (Kirkpatrick), 4,346,909 (Hundeby), 3,457,709 (Kilberry), 4,460,193 (Dietz), Canadian Pat. No. 973,367 (International Harvester) and in brochures issued by Coop Implements and versatile. In many of these arrangements an additional wheel is added to the header frame at a suitable location so the header frame is supported on three ground wheels at spaced positions to form a stable structure. In the Versatile arrangement, the outside wheel can be a dual wheel system which rotates about a vertical axis directly between the wheels. The header frame is supported by a jack and a further wheel is added at the hitch end forwardly of the header frame to provide a stable trailer construction.
The same problem of transportation is also involved in other types of machines such as cultivators, seeders and rakes. Examples of transport systems for these machines are shown in U.S. Pat. Nos. 4,026,365 (Anderson), 4,049,061 (Van Der Lely), 3,778,987 (Rankins), and 4,119,329 (Smith). Other examples are shown in French Pat. No. 2332690 (Herriau) and British Pat. No. 1563852 (Amazonen). In these machines the system employed involves either the carrying on the frame of an additional wheel which comes into play only at the transport position or a system in which the frame is carried on front and rear castor wheels which rotate at 90.degree. to take up the transport position thus supporting the frame on either side as it is pulled longitudinally.
However the machines of this type including the cultivators, seeders and rakes together with the pull type swathers are carried in the field by the ground wheels themselves and hence it is a conventional matter to move those ground wheels to support at least part of the load of the device during the transportation mode. The conventional header is however conventionally supported by the tractor unit and any wheels such as gauge wheels are generally there simply to provide a biasing or lifting force but not intended to support the full weight of the header.